SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'bd3d0855f03752777f97fd43ee4e75dfed281deb9241af8cb850a2effac0d7b8' 
  AND token = 'UvfiBeuDJHfudqvMMXoe3ViD+VctALSg+F0hEeX9nSY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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