SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8aad66725b05adc848492263330781103ace1524b2df0899912622432ce0f2c3' 
  AND token = '3SYwQlaCYOBhJ7vKRYR5b0cs5R6mjkEdzHujQWnH+/Y=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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