SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a75a6df2ae3547576082aebc6c15094cb8327fd7182efc38f88059fe0f66c42b' 
  AND token = 'vSLreyFOIYqBHEyQdpekDw7qtP4me9tGV+1TL9+CSS0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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