SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7dce3fad124a714dd5b5b4c137e38ab377daa46430055c046a979c40d0f4b600' 
  AND token = '5rdH9cyAoR1JLFXsxCNImXX+VNaxhnXcXrdFP0i5pvo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00045

JSON explain

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