SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e2b7ee01852347379923164a5137b5bac945d0451d4ef44a67a16ba0aba510c2' 
  AND token = 'FJJpxTvMNZ/zBmvgIgtNpWrq1pieAqRgsRWijC28d+w=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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