SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e266ca77e6bdec5313ed98d09ce44c27cc341661a062535b682c6aff309de66b' 
  AND token = 'jPBDUFxZFXj41rLHQxxp4PSDabZNTyVoCShxM/vWj4w=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00043

JSON explain

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