SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f9ea584c2fbbca92224b1b075ebc6696a1d8717be210e711c8666dadfa5f8e68' 
  AND token = 'lk07b8+0F+/wabZJpkntLJ2yYKA4xQLazwCaVWjo2yw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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