SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'cab7508612fd41f9d850a1182ce061981f53034dbd99bb59473a79455c802e02' 
  AND token = 'A+jkvpx8hQT6KCF+1Mlvw6ow2GrxAcsUEgPeDnjpr0E=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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