SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '378eb5ce551448ff35ad84e39b4a31da14010834cf3c33951b95aba098fff93a' 
  AND token = 'mgfN/TR9pKn1B8J06Zexc4xQTlBdFHWGfuaVoE1S1X8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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