SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f5deddd1284e9d96f3747d9eaa4949bf1e491f190d6bfc8546e792f5f79aa144' 
  AND token = '0IpRWvdRMLNkLWRakCqRMBzXYgiCvFeyqnenV0aj6iA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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