SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '27d658d2effff8d7b5aee26bbea4ce2260fdc281255f7f5454b612d944c43014' 
  AND token = 'yCeeBdtdS/oCJgCnmeXWGINA1Sef99ByhNIxGy2Fp6w=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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