SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '342ebf2f11f2f96010dcc2f78961f5bc7a2bfa5a5641c631be936d801627cfa5' 
  AND token = 'zrYyH2c8GGnBjvBxhDGFTouyosNAuGEILhy4ZuPNPdo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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