SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3b61a8142c68c97345746c7ad6a7cd51b633c9882cc8f0727b74b3e8d63b7428' 
  AND token = 'wpFoZ70J+BSOEftXjZLufhN0I41WIGzheQvxdiUR/2Y=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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