SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0ac54962ec85536cf2cdf3b3dd5d77f3e76fc9b0819a2106ed86adc2dcb3c274' 
  AND token = 'I9HpZO+ghiz3qKAv/cfvTL9OGvUdXOvaBx8W5NpZTDY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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