SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'cd6db137f75325ffd68ded65d2c0530f660c74d9c67d38a7c20bff4b1d9d4b83' 
  AND token = 'MfpLMgZaQ72sHP/atXK66wKdDLzDnEBqTQIAKyN4r/I=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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