SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5cea97c808eeee2aaac6b209daae5af3ce3e13e39135ba6396ccd965f366d85f' 
  AND token = 'kbvTRP/bBkcQSBq1P5doiIyrLDT29zBeIbf921knams=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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