SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a412bf1683958b0be1cd324907a90d31b00405bcbf1c5dc42babb221e8da8cfb' 
  AND token = 'TFlL8ieg3vN2Y28+7WSt1dd0y0kTREAHTBCP0qu47P0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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