SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '77f7bb932731e31be31d1287f2c30100788ec4c24f9518dc11bcb1ded7904560' 
  AND token = 'zg8uJ8Wu0thWh1y1kJ1xnR6VjvMSkiMVpB2/Mz5BVtY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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