SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '392f907f863e53544734af2aed21b65312dfcdd341bbbc34baff37ee23802f4d' 
  AND token = 'GvVOFuAc7ViH/sMsEtveh00KkCFgLV0Lg32OIfJ5+PM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00043

JSON explain

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