SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a3c0859033b13be269ba62839fd901c35523d1becabd2f4ff1904bf2db76ead2' 
  AND token = 'NeTemnBcdnN4FA7AlkB3NMyC5/VSmYYNxiqK4g+h3AY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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