SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '2976af51fcb71ca5e0bba86717b134457d53245ab4811ed4ec5e073798e78b8d' 
  AND token = '91iwdNxlIWHpXKQrslG7R7Nmoq4guiMcJUGC609sH2I=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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