SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8e1c23959607b3761204471afa7b9b4939714e815f9cc2b19cb265bcfe0842af' 
  AND token = 'Gi4y8LETD9NMTioSkYM0NnQOmZkIKJlpwSKJFbEXE4U=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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