SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'da4758cdf10e519e1272b431f52ac21920d983867822464bc76b6e4d1eb011df' 
  AND token = 'YTqw375uuUaByp1qif0AR7vVRlsZHFLTaNqrqLiLSDQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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