SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c1033d25dfa0705a19bcfa6a1579841f62a3d850550adb4b8b7ec55d6d440360' 
  AND token = '0d0BR9miQN4jjQOUTAq8mlla1p5htAclHqIxZf8boHY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00075

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}