SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b158925219144521b78a253c1fabd9f43eedc83df1fcfc82ef33ebc2500de9db' 
  AND token = 'B0Iw0Fx0ByCmXkzjJRpqhPOFNotAUck/15WJ0dQOt3w=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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