SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7bdf6ebcc9752c7c693edd8d1df2edccaa2c00afdcbd90280b6f37101630f14a' 
  AND token = 'nLmV0w/7Ghup4I6um2ZkbWNvxgoUfMFQ3CJEXCFqM1I=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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