SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2ef3c10024073b1391c21345d6c0d52b298f6e06780d3158d68dd8ba79a39c76' 
  AND token = 'pgrth1QC2iXNfyAgZ+Iz0oYSQ8hd8h8zdUVpMBilH2w=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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