SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ba55a0351303be8b5eaafa50813efccadb8ea7e8ce627a37ed523d9225750c6e' 
  AND token = '96BrQeLUyVLBLLQP74Y77X2Iqv+Q2Xxz+mm6cfBC7QI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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