SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd66675aab7ccd5b4318c0b7f355c2f03dac05fbe171a45883326e943976c7d9f' 
  AND token = 'JW1R5jK7Fh8lAp+V4jF2gtDRsoCpbvWyVwQYI4Ldff0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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