SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '85f94e8fe49e8312abbdd5711d3fff8d094fd0618eb4962f387ca230e5d72296' 
  AND token = 'txmtULQmJK0w9OL4p5GkwfbHeTMPkoZT89A8RXzPhUs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00016

JSON explain

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