SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f7ffb06d9b70bd9443fd712ee8b440aa1a9839e90c16609aca267dac1bb11166' 
  AND token = 'Dsi6FJlurmEFQU9vqVGFJ+d+IQSKq5PxBfSHHwpV4gc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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