SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '768080bd87f7070d1fa875becddb9fac727e875534694aa826277f14bfc1db7b' 
  AND token = 'EBM8AKsmrhZTswtI29PLgzcbXGoVBEwtstzHM98+Jys=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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