SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0ef48b78bb2a5b4c65c60d67b6317b380a257a72f0e5601a66d002ee322731db' 
  AND token = 'BuLWZ8yPZWkddTN3S6GfOh4JqkkTQBaEBEBoTlKM44E=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}