SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2c486aed082f092624242bafd948ac0059d858bdca8edf77d7e9702bcc96768e' 
  AND token = 'jkqFGcOmofhRCVd5Zb00L75DNoLpo0NFdh2pZta9BH0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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