SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f271401740e47ab25e92472d8f2262d76cb57257a0932f5ae0a8ba097d2f2b70' 
  AND token = 'gX1Tp9kzyqMGh//uvjdf4gM8NId6gyVf3wquKFTZFug=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00016

JSON explain

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