SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'cd4367fc8e5bfe493c456832ec8a9af38319f2edb511ca82059606cd8108cd6a' 
  AND token = 'L2qqtYXF8rdn8oWZ/jlQ5T2aLB0elHm+bot8fX54WyI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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