SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9913f930e8ac6f4a0b2c244f25fb5adcb7bdf1235056c3bf3732281da080b541' 
  AND token = 'dj/SmzXjgym4JXtN8tiD/QJFk2cthulvUOFcpEQKSaY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00043

JSON explain

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