SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0ab8b1f3c27d05c4b3330616601263deffd0439eeeb1246a57e719ddde1ea92a' 
  AND token = 'yBdVGYo06gk4bpcUWCiBthJTjQDLp7PmB00xV4r1krU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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