SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fb80a1a7f9c7b19599229608a6cd6dc6adc245dc8020fad11f740ca6c25dd35a' 
  AND token = 'VR8lFnXboPdlPIQ0vlI8Gq4rR34GL0IWOPqKrQ1SgLo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00016

JSON explain

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