SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '37ef93bd6c425340d0daa25acc2d26f2653baf57ea02fa350564e358889b9bb4' 
  AND token = 'WlHcXx3GgaxfiCh8FjjakPSUr/khB5GxYaXHAuslUPk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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