SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6b5ae74b4608c3c641edacfacde451ad634be64ec799c22c0be37fc6ffc8ec3d' 
  AND token = 'Gq8rfNQbC4Fia+peovIdvTLnjd/dPDB0Qbdb1UhN1rE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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