SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '587ba351a1dc0726b49bf60a6d58535779a98214d0d038652ac5f0c22fd8209d' 
  AND token = 'LEbGqS/Is0v/5IjwvNoOcp14q+FUkhdGm57wACQBhOU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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