SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'b754d664077639f9d921312cbafc4c3bc90a2c8cce34c28a3796d9a47f48b8d6' 
  AND token = '2lQJDlKayxfT/Uamt4yq3XQ7Z2qlNkx3I2cnHgfWKJg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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