SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '194b1268d8772e8e9b41990c1593d6b83017e28d9e5754b5f88752b10cba85a4' 
  AND token = '8ouykPHzM2GGJ064ndTGfPAHMghozAfttkskChRRhUw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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