SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '988a8f8a00edf94e2f9d05152d791dbfcc4eaf2d4995438db981d1c5d815a4e5' 
  AND token = '+SEfkrLKuP4rJXEd8tZHJRhOTw9vMlxxCRZuqWAhVqs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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