SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b97eee400131185d7314b1d493e41fe7508e47f715a373286254db7931ac56b3' 
  AND token = 'EdVGpYeOGiHOVUzN2y1OqWkjKy5Dyv4YPMAnhmB3UXk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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