SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0b6dcc527b9f59ddbbbc6406d8c1c726985855eb0f12f768d6364e27282b4c1a' 
  AND token = 'GCxYPznRinhHi8IlzhpB2KKsZXqW/mLAastuFJJ6Fqc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}