SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ae9abbfaef6f581bf9237cd1a46983069bac18b06850abf559b509e2c86091e9' 
  AND token = 'cpDrDpOEaKnv9iv04EwkECBULSx2dq6CptXKP8FbfOg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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