SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b34599754fa9ac676bba42b408742028342345694769f34d05cd2e0f3c63deb7' 
  AND token = 'rPDjkDKVOD247J/j2B3Hn0pMENNPlwpSG6kZvN1tzbw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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