SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6d8d107f7376c5189044190886b34913adfcfd23a9cd4a4f9cf8551f97a5d91f' 
  AND token = '+0+15yhi4vuKDRECTCWyw/sUnGSRvtVOqeqmzkWOlW8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00077

JSON explain

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