SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '44800bf51bcc3405b034e1aa4368e58e977f7e279b8dbe3455adfd4c30f41f87' 
  AND token = 'Egu0EmBmgGrYIWf/CdeN2Lq4urOIyEEN9suKkYE4Vwc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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