SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'aa953974056b42454d71f443e37844daf72c86fd19359d29db41040f17325a2e' 
  AND token = 'SD0OnjYfwAnlBU8gYG1JMrqIPzUP/rhD51LZe0ev27c=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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