SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e3c646f05d60b49bbaf543a0566d7f02767ef3e948b45bae3683145ac44825ed' 
  AND token = '+uLLyMGMSJZmydbtIMKMEyHpO8doGDtJGSA5TwjkkK4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00040

JSON explain

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