SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd795cbbdf33d27befc010361d44edbf91510182572191babbd6a94cb3e537d72' 
  AND token = 'nPmRoczJmNTS5MTmJ9zEMIHa99zHxA2oNdW+ckBxWuY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00040

JSON explain

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