SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b517a85f0bc8fdd36ca1811aad9a38541c875f47a3aa757c94044c09d986987e' 
  AND token = 'lLqid+4PdXHZuApSMMzajlGUNxAKqruulZmJgiUBN6A=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00044

JSON explain

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