SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9386e1f7751f2c29833131a20e638f14a18d02ba0d32a49695ecf287e62e3b43' 
  AND token = 'zCVktwYp1+gBocK6xtiv/cGrE8r1BqxXKkIBz6rEzYs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00069

JSON explain

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