SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6c8b989b691d09812e717653e43e3e8ccca15eee52c126e2fdf0a9186181bea9' 
  AND token = 'XX/Q6JNNhlVHUaqP+vVCyCI52w+DM1Q4vueSIPBPnC8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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