SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f873d7f96bc84a62a4f98d445b423ce2c571068c7bed453a1bc7291b75c8b050' 
  AND token = 'SHfcVG8qHYOx1jvp9AiNQaLze4VT2QixcS4WztFsfB4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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