SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b56fa67877c32a3a76fbf20e59dc481cb7d06089ca6125536de96f1ce97ab604' 
  AND token = 'pAT9EGnGzWjxFvpbYSEbY/DMM7++bGkoJnsx7xUHfu0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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