SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1210a4c0be6203be44fd747dbc75a706f8a46ab7c412c2912c63690bc5702d12' 
  AND token = 'oyP0vlGw/wBmN1ZRDFUWW9WHw3fdVPYR7avemvWvH64=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00043

JSON explain

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