SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '71de778837d0f80d8601ce490977f7536daf25626c4f38668f60c5b703b128bd' 
  AND token = 'eQmKmyzC1QeZYG1Bru56K3d+NvzuhTazLCPMRu/gibM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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