SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e2cd3789d99e9a1a5d9ba3dceaead8133b3700ab4b172cd90b063cc7da7403a3' 
  AND token = '18BljGl8auThNFu1x/dYsqIVEnNF/dZjIzjeYvrDxS4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}