SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '76abc11905c6a629b308b84273dd5db8454d22dae04d12ce9f187e145e59dc81' 
  AND token = 'NfbHwhiBmBRDNKl//MsPpk+gxv0Ry1ZELQHU6fFfYqo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00010

JSON explain

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