SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fde8fcbdd7cf0c6e6a050aa393cb233ff7fe440f8502200931dbb358148428f9' 
  AND token = 'f5mEgOEPstehmGha3QPGu8zxpJtvCxKofd5KjCqtle4=' 
  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"
    }
  }
}