SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7eff445bd4bc2a44ee63729462de971753689216dd28c2f29412cf05b16407c2' 
  AND token = '+o5nouOjMRsIqzF2IPjGeoDAmlOsq2JMUIyjZTZL9/s=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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