SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2c0c77b719e661facc9dfd14bdac937c5463e90eb5039eb77999cfc2b08ac49a' 
  AND token = '94xJJFS8P5PrXOnnwt/fjPdvJXoQGis++Ck61lHi6Qk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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