SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4b2f117a830142e5f8a406687b98460d1150575b4c894e6758e337b83d9b9fee' 
  AND token = 'bvCpuSL+wtiQoTLa5vUE2rV9BEGqzzqFopK3QyP29oU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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