SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'be6895487f0a6416edba8b9ff23367876129f2196c3656aed5a98e2ce635cd25' 
  AND token = 'DhfcLb8UQDeni5JceGTZs+QMauGY6ctNkcIwWOWjl88=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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