SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '16b2702bedb7555542ccae4abee70061befa72c1f8cbceb2a777f3b096ec7a12' 
  AND token = '5uqnjeg6+fG1CZihic6lby+hOFcyGMCEqahBF4wQcYQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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