SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '408ef86c52bbda1819678080ce9a6e31c93adde8c517814a05b9b4be57e40f7d' 
  AND token = 'igBpB92HRTE/nmicvrEtXaYkCrywNYsjzmyx5Inf1fE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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