SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'ae6bc636cf485fc253919021e3bc1548ba9e4962489ab57cef775431e2a1c671' 
  AND token = '8R+aFWm3jsAZPr9RXFrvqiiqyQefhxNPtXnV/UClYjw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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